In the rapid development of computers many advancements have been seen in the areas of processor speed, throughput, communications, and fault tolerance. Today's microprocessors have achieved speeds of 2 Ghz with no upper end insight. However, no matter what the component or how fast it operates, communications still must be established between one component of a communications system, computer, or other form of electronic equipment. In the early days of computers such communications between components were established via wire wrapped boards. A substrate would have numerous holes drilled into it and small posts embedded in each hole and extending below the substrate. Wires would then be wrapped around each post to connect one post to another. The electronic components would then be inserted into holes contained in each post. However, as can be imagined this was a cumbersome, time-consuming task was numerous error prone manufacturing stages.
Wire wrapped boards were completely eliminated through the development of multiple layer printed circuit boards. A cross-sectional diagram of such a printed circuit board is illustrated in FIG. 1. This printed circuit board (PCB) 10 is made up of several layers of dielectric material 20. This dielectric material 20 may be composed of a glass epoxy fiber or other nonconductive material. Embedded on the surface of this PCB 10 may be contained surface horizontal conductive features 30. In addition between the layers of dielectric material 20 may be embedded horizontal conductive features 50. These surface and embedded horizontal conductive features 30 and 50 would serve to provide power to the printed circuit board components and establish communications between printed circuit board components. Various layers of surface and embedded conductive features 30 and 50 would be connected via through holes 40 which may be plated or filled with a conductive material and used to establish connections between PCB components and various dielectric layers 20 having surface and embedded conductive features 30 and 50.
However, due to the limitations of utilizing surface and embedded components, conductive features 30 and 50 along with through holes 40 several difficulties arise for PCB designers. First, shielding of selective components within the PCB 10 from electromagnetic radiation may prove difficult. Second, providing greater power and heat dissipation to selective components in the PCB 10 may prove to be more difficult. Third, using through holes 40, it may be difficult to connect inner layers of conducted features on embedded dielectric layers 20 without completely drilling through the entire PCB 10.
Therefore, what is required is a printed circuit board and a system and method in which shielding may be provided for selective portions of a PCB 10. Further, this system and method should provide a printed circuit board with greater power routing and heat dissipation both in the inner layers of the PCB 10 and the surface layer of the PCB 10 to some determined depth. In addition, printed circuit boards produce according to this system and method should reduce the number of through holes 40 required to connect various surface and embedded traces such as conductive features 30 and 50.